190 PEINCIPLES or PLANT-TEEATOLOGT. 



and carpels was^ihe circular swelling normally occurring 

 in the female flower and which some authors regard as 

 a disk, others as a rudimentary calyx (PI. XL VI, fig. 8). 

 The presence of carpels in this position proves that the 

 anthers topping all these axillary structures which are 

 devoid of any articulation represent entire stamens in 

 which the filaments have become quite suppressed : a 

 very i-are case. But it is, in part, comparable to the 

 normal cases on the female side of the Conifera3, 

 Gnetaceae, and Gvikgo in which the carpel is reduced 

 to an ovule, at least according to the view here held 

 with regard to these structures. 



Usteri describes the transformation of male flowers 

 of the papaw [Garica Papaija) into hermaphrodite 

 flowers by the change of some of the stamens into 

 carpels ; transitions between these two organs were 

 observed. 



Again, there is the case of purely male flowers 

 becoming female by the change, not of a portion only, 

 but of the whole andrcecium into a pistil ; this can be 

 seen occasionally in the male catkins of the willow, 

 e.g. in the sallow {8alix cinerea), giving rise to an andro- 

 gynous inflorescence; the two transformed stamens 

 usually become united by their margins to form the 

 bicarpellary pistil of the normal female flower ; and it 

 is interesting in this connection to know that in the 

 normal male catkins the stamens frequently become 

 thus united, and this is constantly the case in the 

 variety monadelpha. These facts clearly prove the 

 close alliance which exists between stamens and 

 carpels. 



Numbers of catkins were examined from a male 

 tree* of this species; most of these bore flowers in all 

 of which the two stamens were represented by two 

 quite separate carpels borne on long stalks (PI. XL VI, 

 fig. 10). One catkin consisted entirely of flowers in 

 which the two carpels were united above, but bore 

 pollen-sacs on the inner side of the gaping base 



* Kindly sent by Mr. W. H. B. Fletcher, of Aldwiok Manor, Bognor. 



